Fundamentals of Geometry
- Free online book on geometry in pdf format. Contains material not easily found elsewhere from detailed exposition of elementary absolute geometry based on Hilbert's axioms to more advanced topics.

Xah's Personal Page
- Features an illustrated dictionary of special plane curves, a paper on wallpaper groups, mathematics image gallery and links to software packages.

NPR : Mathematicians Get Crafty with Geometry
- A husband and wife from Cornell University have come up with a crafty way to illustrate high-level geometry concepts -- by manipulating yarn into models that help explain the curvature of spaces. The mathematicians talk with NPR's Jacki Lyden about hyperbolic crocheting. [4:47 streaming audio broadcast]
(March 13, 2005)